Growth works differently here. It's called evolution and can happen quite suddenly. Not too dissimilar from the metamorphosis from a caterpillar to a butterfly.

_{[He's contemplating whether to show her Big Red or not. It is her Arcanine, after all - but if she doesn't know yet that she's been here before, he doesn't really want to mess with her head by telling her that. ..not to mention that a six feet fire dog in itself can be pretty startling.]}